Exhaust-gas heater



Nov. 26, 1929. J. sUNDAY EXHAUST GAS HEATER Filed 001;. 2'7, 1926 Patented Nov. 26, 1929 maar JAMES J. SUNDAY, OF DETROIT, MICHEGAN, ASSGNOR TO STANDARD TUBE & MANU- FACTURING COMPANY, OF DETROT, MICHIGAN, A CORPORATION OF-MICHIGAN EXHAUST- GAS HEATER Application. led October 27, 1926. Serial N'o. 144,438.

This invention relates to exhaust gas heat-` ers for automobiles, and it has to do more particularly with a heater of the type in which heat fromthe exhaust gases is transferred to fresh air, which is supplied in a heated condition to the interior of an automobile.

Heaters of this general type have been proposed heretofore, but these have been objectionable because they do not overcome certain difficulties which are encountered. One of the things which must be guarded against is the creating of a back pressure upon the engine by causing the exhaust gases to flow through the heater. l/Vhen this occurs the engine cannot operate eficiently. The heaters heretofore proposed have' been of a comparatively large nature in order that the air be adequately heated. A heater which is un- Y duly large is objectionable because it is difficult to install, and in some automobile structures, it is impossible to install sucha heater because of interference by such things as radius rods, and also because of the size of the muffler. Another objection is that when exhaust gases pass through a heater, the pulsations set up a vibration in the heater, or rather in the walls of the heater, so that the pulsations of the exhaust gases are rendered plainly audible.

This invention aims to provide a heater which affords a large heat exchange surface without the necessity of a heater of unwieldy dimensions. Accordingly the heater is of a flat construction as distinguished from one which is round in cross section, and this construction is advantageous because the heater canbe placed angularly and installed in places where the old type of construction couldnot be installed without extensive structural changes in the automobile construction. The invention contemplates a heater which is shaped so that the exhaust gases are caused to travel therethrough in such a way that the transfer of heat is efficiently accomplished, and at the same time, the heater does not increase the back pressure of the exhaust gases on the engine. According to the invention the walls of the heater are supported, or braced, so that the pulsations of the exhaust gases do not set up a vibration which would result in objectionable noises.

A satisfactory form of the invention is shown in the accompanying drawings wherein:

`Fig. l is a plan view of the heater with a part of the exteriorcut away thus showing a part of the interior.

Fig. 2 is a sectional view taken on line 2-2 of F ig. l showing the exhaust gas chamber, the fresh air chamber, the manner in which the walls are supported, or braced, and showing the additional heat transferring surface.

Fig` 3 is a sectional view taken on line 3-3 of Fig. 1 showing how the outer portion of the heater may be secured around the inner portion.

Fig. l is an end view showing the two inlets, one being for the exhaust gases and the other being for fresh air.

Referring to the drawings, the heater will be seen to consist of an interior member l and an exterior member 2. `The interior member may be made in any desired manner, but it is preferably in the form of a single casting. The member l is shaped to form a relatively broad, flat chamber having'walls 3 and 4 which are connected together at their ends, as shown at 5.

At opposite ends, this member is provided with openings l0 and ll, one of which is for the inlet of exhaust gases, and the other for the outlet. rlhese openings are preferably round and are adapted to receive the ends of the exhaust pipes 12. The exhaust gases enter one of the'openings, pass through the chamber between the walls 3 and 4, and' then pass out of the chamber through the other opening. The walls of the exhaust gas chamber are shaped, as shown at la, so that there is more or less of the gradual change from the circular cross section of the exhaust pipe to the flat, relatively broad cross section'of the chamber in the heating unit.

' As shown in Fig. 2, the walls 3 and 4 of the exhaust gas chamber are tied together by, posts 15. These posts are cast as an integral part of the interi-er member l and serve to bind the walls` together and makethem rigid so that the tendency of the pulsations ofthe exhaust gases to set up a vibration in the walls is overcome. By this arrangement no additional noise results in the use of the heater, for even though the gases are caused to be somewhat flattened out so as to flow through the chamber, there is no vibration in the'walls of the chamber.

In order to increase the heat exchanging surface, each Wall of the exhaust gas chamber is provided with a multiplicity of projections or teats 17. These are also preferably cast integral with the walls.

The outside covering for this interior exhaust gas receiving member is preferably of relatively thin sheet metal. This exterior member is made up of two sections disposed on op osite sides of member 1, and these sections ave their edges secured together as by means of a lock seam 20. While other ways of securing the edges of the two members .together may be used, the lock seam is advantageous in that the members can be secured around the casting and their edges locked together by a press operation. Each sheet metal piece is provided at each end with an extension 21 which is arcuate in its final form. These are arranged inropposed positions so as to form at'one end an inlet for fresh air, and at the other end an outlet. The meeting edges of the extensions, shown at 22 (Fig. 2) may be somewhat spaced apart, or may be overlapped so that a suitable conduit may be placed thereover with the members under compression. In this manner the air conduit f may be held in place. The sheet metal portions of the exterior part 2 are drawn down tightly over the'projections 17 so that the air is causedto flow aroun'd the projections. By this arrangement the projections perform the additional function of supporting the sheet metal Walls, and since the Walls are supported against vibration, the outer walls are Aalso given support. This structure affords an air heating chamber 25 which is divided centrally by the exhaust gas chamber and which has an inlet and an outlet disposed at opposite ends and communicating Y substantially equally with divisions of the air heating chamber.

It will Vbe understood that the device is inserted in the exhaust line of the automobile, and the exhaust gases pass through the chamber 6. Fresh air is passed through the cham ber 25. The supply of fresh air may be obtained from any desired point, and after it passes through the chamber, is then con- 'ducted tothe interior of the automobile where a suitable'radiator may be used. f The movement of the gases passing through is slower than the movement in the exhaust pipe, and yet the proportions of the chamber, as comred ,to the size of the exhaust gas conduit,

are such that there is no increase in the back j pressure. This slower movement of the exhaust gases` through the chamber causes the` walls thereof, and the teats or projections 17 to be adequately heated. The fresh air passing through the passagewayQ contacts with the walls andthe projections which afford additional heat transferring surface. Y The Whole structure forms a compact flat unit which can readily be installed, especially since the thickness of the unit is not substantially greater than the diameter ofthe exhaust line, and which is so constructed that the walls of the exhaust gas chamber are tied together so that they are not subject to vibration, and also the sheet metal walls of the exterior shell are drawn down over the projectionsso that they too are not readily subject to vibration.

Vhile it is advantageous to make the interior member of a casting, the same may be constructed by the useof sheet metal parts, and in this case, the posts may be in the form of bolts or rivets instead of integral parts of the casting. Likewise, the projections which aor'd the additional heat transferring surface could be in the form of separate pieces afxed to the sheet metal wall, as by means of riveting, welding, or the like;or, the proj ections may be stamped in 'thev sheet material. The precise number of posts is not material because it would be desirable to have more posts with a larger structure; also, the. number of posts used would depend upon the thickness of the walls of the interior unit; thick Walls would require a smaller number of posts whereas a thin wall would require a greater number of posts. l

The exhaust pipe 12 can bev connected to the inlets 10 and 11 in any expeditious manner as by the means of a bolt passing through both members. In producing the article, the inlet and outlet may be formed' of relatively thick metal, as at 26, and the sizel may be such as to fit over a smallv sized exhaust pipe. n

1. An exhaust gas heater comprising a rela-` tively flat member adapted tobe inserted the exhaust line, having a chamber for the passage of exhaust gases therethrough, la

multiplicity of projections on opposite sidesof this member, and an outside casing over' the said member which forms'a chamber for f the passage of, air with the saidl projectionsI lying within such air chamber to increase-the heat transferringl surface, said exterior casing lying directly upon said projections whereby the air is` caused to flow around the same. t

2. An exhaust gas heater comprising a member adaptedto be inserted inthe exhaust. line Vhaving a chamber forv the passagefof exhaust gasestherethrough, said member being shaped so that a broad, flat chamber is provided, a multiplicity of heat transferring projections on the exterior of said member, and an outside casinoV over said member which lies directly upon said projections to form a chamber for the passage of air with the projections in such chamber, and posts connecting the walls of the inner member for bracing the walls of this member and the exterior member against vibration. y

3. An exhaust gas heater for automotive vehicles which comprises a hollow member adapted to be inserted in an exhaust line, said hollow member being relatively long and relatively lat as compared to the diameter of the exhaust line, and of a width substantially greater than the diameter ot the exhaust line, a casing around this member which is shaped similarly to the said member and which is in spaced relation therewith to form an air chamber, the said first mentionedmember, together with the casing therearound and spaced therefrom having a combined thickness not substantially greater than the diameter of the exhaust line.

4. An exhaust gas heater for automotive vehicles which comprises a hollow member adapted to be inserted in an exhaust line, and having an opening at each end for the passage of exhaust gases, said hollow member being relatively long and relatively flat as compared to the diameter of the exhaust line, and of a width substantially greater than the diameter of the exhaust line, a casing around this member which is shaped similarly to the said member and which is in spaced relation therewith to form an air chamber, the said iirst mentioned member, together with the casing therearound and spaced therefrom having a combined thickness not substantially greater than the diameter of the exhaust line, the said casing being shaped to provide an air inlet and an air outlet at opposite ends respectively, and each in close proximity to one of the openings in the iirst mentioned member and the combined width of the inner member in the casing being not substantially greater than the width necessary to accommodate the two aligned openings at each end.

5. An exhaust gas heater for automotive vehicles which consists of a relatively fiat hollow member having openings at opposite ends, said member being adapted to be inserted in the exhaust conduit of an internal combustion engine with the conduit communicating with the openings, and a relatively flat sheet metal member secured around the first mentioned member and in spaced relation therewith to provide an air chamber, said sheet metal member being shaped at its opposite ends to provide an air inlet and an air outlet, said inlet and outlet being disposed at the ends of the heater and each in juxtaposition to and lying in the same plane as one of the openings at the end of the said hollow member.

In testimony whereof I aix my signature JAMES J. SUNDAY. 

